Vascular Occlusion Systems and Methods

ABSTRACT

A blood vessel occlusion system and method includes a handheld probe including a power source, the probe being adapted to transmit energy from the power source through a body surface and into a target blood vessel, for example a varicose vein. Further included is a manual or automatic switch mechanism adapted to enable and disable the power source in response to a predetermined level of compression applied, by means of the probe against the target blood vessel. When the blood vessel is compressed sufficiently to collapse and substantially slow or substantially prevent a flow of blood therethrough, the power source is activated and the vessel is cauterized, leaving the blood vessel in a condition that is resistant to recanalization

BACKGROUND OF THE INVENTION

The present invention generally relates to medical apparatus and methodsfor medical and cosmetic procedures. More specifically, the inventionrelates to noninvasive apparatus and methods for occluding bloodvessels, such as varicose veins.

There are a number of conditions in which there is a need to shut downand halt the circulation through particular blood vessels. Examples ofblood vessels in which one may desire to reduce blood circulationinclude varicose veins, spider veins, hemangiomas, teleagectasias,hemorrhoids and gastric and intestinal bleeders.

Veins are vessels that carry blood back to the heart. There are a seriesof one-way, leaflet valves spaced throughout human veins. The valvesform an integral portion of the skeletal pump which squeezes blood outof the veins whenever muscles contract. When functioning properly, thevalves prevent blood from flowing in the retrograde direction (e.g.,away from the heart) back into the vein portion upstream of the valve.

A varicose vein is recognized as a vein which has permanently lost itsvalvular efficiency and, as a result of continuous dilation underpressure, in the course of time, has become elongated and tortuous.Varicose veins occur frequently in the legs.

In many people, particularly women and those predisposed to thecondition, the one-way leaflet valves within the leg vein often becomedysfunctional and fail to seal completely. Thus, the portion of veinbelow the dysfunctional valve must support the weight of additionalblood from the vein portion above the valve. The extra pressureincreases the diameter of the vein, leads to additional valve leakage,visible varicose veins, and possible ulceration thereof.

In severe cases, varicose veins are treated by surgical excision, inwhich the vein is removed entirely from the body. The vessels to whichthe vein is joined are sealed, as with ligatures, at each attachment.The varicose vein is then cut and removed through incisions along thelength of the vein. This process is documented to be at least a hundredyears old.

A more recently developed, though similar technique is accomplishedthrough a series of incisions, for example incisions of about 1-2millimeters, along the vein. The target vessel (i.e., varicose vein) isthen “hooked” with a stripping device and removed.

Rather than removing the vein, surgical repair of a varicose vein may beperformed. Ligation or tying of the vein, through a small incision highin the leg vein, may be performed as a means of eliminating the sourceof pressure that distends the varicose vein. It is also known to apply asilicone band below the dysfunctional valve to cause narrowing of thevalve.

Sclerotherapy is a technique that uses hypodermic needles to injectsclerosing agents into varicose veins to elicit clotting and ultimatelyscarring within veins to achieve venous occlusion. To treat largevaricose veins, this technique requires the use of large volumes of,and/or highly caustic sclerosing agents. Such techniques carry risks ofcausing unintended thrombosis and embolization, among other things.

Noninvasive surgical procedures have also been developed for treatingvaricose veins. One such procedure utilizes an intense laser or pulsedbroadband light source to treat veins between about 0.1 mm to 3 mm indiameter. These techniques are able to prevent the flow of blood throughthe veins by heating blood within the veins to form stable blood clots.

Noninvasive procedures for treating vascular disorders other thanvaricose veins have included the use of light to cause coagulation ofsmall veins near the surface of the skin. For example, U.S. Pat. No.5,405,368 entitled Method and Apparatus for Electromagnetic Treatment,discloses a method using high intensity, broadband incoherent light tononinvasively treat skin disorders. The pulse length of the light isselected to uniformly heat the entire thickness of the vessel as much aspossible to achieve coagulation of the blood in the blood vessels. U.S.Pat. No. 5,344,418, entitled Optical System for Treatment of VascularLesion, discloses a system using a narrow band arc lamp for radiatinglight through a lens in contact with the skin, the peak wavelengths ofthe light being chosen to be absorbed by the blood to cause coagulationof the blood. A cooling mechanism is provided for protecting the skinfrom overheating.

In both of the above referenced patents, the disorders treated are smallveins, i.e. veins of less than 0.5 mm in diameter. The target vesselsmay comprise port wine stains, telangiectasias, and cherry and spiderangiomas. Although these conventional devices were developed fornoninvasively treating vein abnormalities by heating, and coagulatingblood by using light, it has not been suggested that the disclosedtechniques would beneficial in treating larger vessels, such as varicoseveins.

Percutaneous procedures have been used for treating varicose veins. U.S.Pat. No. 5,437,664 entitled Apparatus and Method for Venous Ligation,discloses the use of radio frequency power delivered via a device placedthrough a skin incision to shrink varicose veins. U.S. Pat. No.6,398,777 entitled Endovascular Laser Device and Treatment of VaricoseVeins, discloses the use of laser radiation delivered via an opticalfiber placed through a skin incision to close varicose veins. Thesesystems and methods require an incision to be made in the skin of thepatient in order to treat the veins, and thus, provide a substantialrisk of infection and require a healing period after the procedure.

There is still a need for simple, yet effective systems and methods fortreating veins non-invasively without risk of injuring adjacent tissue.The present invention provides such systems and methods, described indetail below.

New blood vessel treatment systems and methods have been invented. Ithas been found that application of sufficient, but not excessive,pressure against a vein section, for example a vein section recognizableas a varicose vein, during non-invasive transmission of energy into thecompressed vein, will safely and permanently interrupt the blood flowthrough the section of vein and leave the vein in a condition that isneither visible by protrusion nor by discoloration, and is resistant torecanalization.

In short, apparatus and methods are provided specifically adapted andconfigured for this purpose. The present invention provides a costefficient and straightforward treatment of blood vessels, such asvaricose veins, with few, if any risks of injury to adjacent tissues orskin. Because the system is noninvasive and does not require evenmicrosurgical incisions, there is almost no risk of infection to thepatient, and a patient experiences a short recovery time. Because nomaterials are inserted or injected into the body, there is little riskof embolization and little risk of inadvertent ligation of othervessels. Furthermore, the present apparatus is designed with uniquesafety features that are developed toward reducing the level ofguesswork required for safe and effective operation thereof.

The present invention is further distinguished from the prior art ofnon-invasive venous ligation treatment in the mode of lesion creation.Some prior art uses the transcutaneously transmitted power to heat theblood within the vessel to a temperature adequate to achieve thrombusformation; whereas the present invention uses the transcutaneouslytransmitted energy to heat the walls of the vessel adequate to achieve astable closure of the blood vessel walls.

In one broad aspect of the present invention, a varicose vein treatmentapparatus is provided which includes a handheld probe coupled to orincluding a power source for transmitting energy transcutaneouslythrough a body surface and into a target blood vessel, for example avaricose vein. Further included is activating means for activating thepower source in response to a predetermined level of compression appliedagainst the target blood vessel. The activating means may be manually orautomatically controlled. For example, if an operator determines that adesired amount of compression is being applied, a person, such as theoperator, may activate the power source to apply energy to the targetblood vessel. Alternatively, the activating means may be automated sothat when a desired amount of compression is being applied, the powersource is automatically activated to apply energy to the target bloodvessel. The application of energy in the presence of moderatecompression will promote the formation of a stable lesion andcauterization of the target vessel which is effective to occlude theflow of blood through the vessel.

Importantly, the predetermined level of compression is selected based onan amount of compression of the vessel that is sufficient for pressingthe opposing inner surfaces of the blood vessel against each other,substantially slowing or substantially preventing a flow of bloodthrough the target blood vessel. By positioning the opposing innersurfaces of the blood vessel in proximity to each other, energy providedby the power source is effective to join the opposing surfaces to eachother to create an occlusion in the blood vessel. The occlusion may besufficient to completely prevent blood flow through the blood vessel, orit may be sufficient to reduce the inner diameter of the blood vessel toreduce the amount of blood retrogradely flowing through the valve, andthereby reducing, and preferably eliminating, the varicosity.

Preferably, the power source is a device that is capable of generatingsufficient energy to cause opposing sidewalls of a selected blood vesselto be effectively coupled together to reduce, and preferably prevent,the flow of blood through the blood vessel. The power source may be asource of electromagnetic radiation. In certain embodiments, the powersource is a broadband light source. A useful broadband light source is alight source configured to emit radiation having a wavelengths in arange of between about 300 nm to about 2000 nm. In certain embodiments,the light source is configured to emit radiation in a range betweenabout 300 nm and about 1100 nm. The power source may include a lightsource capable of emitting visible light, and/or near-infrared light.The power source may also include a laser. In additional embodiments,the power source may be a source of microwave energy configured to emitmicrowave energy having a frequency or frequencies in a range of betweenabout 0.9 GHz to about 3 GHz. In other embodiments, the power source maybe a device configured to emit radio frequency energy having a frequencyor frequencies in a range from about 100 kHz to about 3 MHz, In stillfurther embodiments, the power source may include an ultrasound deviceconfigured to deliver ultrasound energy to the desired blood vessel. Inadditional embodiments, the apparatus of the invention may include acombination of any of the foregoing power sources. The energy emitted bythe power source may be delivered continuously, or the energy may bepulsed, or the energy may be gated. The energy may be gated by theactions of one or more shutter devices, and the like. Focusing means,such as an aiming lens, may be provided to concentrate the energy sothat the power intensity is higher within the vessel than in the skin.

In one especially advantageous embodiment of the invention, theactivating means for activating the power source includes a switchmechanism adapted to enable and disable the transmission of the energy.The switch may be operator controllable, or it may be automaticallycontrolled. Preferably, the switch mechanism is further configured toenable the transmission of energy only when the applied compressionagainst the target vessel is within a predetermined range. The apparatusis intended to cauterize the target blood vessel while the vessel isheld in a collapsed state. The compression serves a multiple purpose bycontributing to the efficiency and effectiveness of the cautery, thestability of a lesion formed thereby, and a desired cosmetic result.

More specifically, the switch mechanism is adapted to disable thetransmission of the light when the applied compression is either toosmall or too great, i.e. inadequate or excessive. Preferably, the levelof compression applied to the vessel is sufficient to cause contactbetween the interior vessel walls and substantially prevent blood flowtherethrough. Even more preferably, the level of applied compressionprevents blood flow but does not entirely eliminate the presence of asmall amount or volume of blood remaining between the vessel walls. Whena volume or aliquot of blood remains in the compressed portion of theblood vessel, the relatively high power absorption of the bloodcontained therein may enhance heat transfer into the vessel walls. Thisallows for the formation of a stable clot, stable vessel closure, andinterruption of subsequent blood flow. In addition, it is important thatthe amount of applied compression is not excessive so as to interruptblood flow in nearby arterial vessels.

An object of the present invention is to heat the opposing walls of theblood vessel as they are held in intimate contact with each other. Whenthe constituents of the vessel walls are heated above the proteindenaturization temperature, this presumably allows formation of newmolecular bonds within the protein structures. Some of these new bondseffectively attach the one vessel wall to the opposing vessel wall.These bonds are believed to securely hold the vessel in the collapsedconfiguration.

The means for activating the power source in response to a predeterminedlevel of compression may, for example, be comprised of a load cellwithin the apparatus that would enable functioning of the power sourceonly when the load cell indicates that the applied pressure is withinthe desired range. Other means for permitting operation of the powersource only when the pressure is within the desired range arecontemplated. For example, electrical contacts within the probe may beprovided, said electrical contacts being separated by a spring supportedstructure. More specifically, only when the spring is compressed withinthe desired range will the contacts overlap and thereby complete theelectrical circuit to enable power to be delivered to the patient.

Means may also be incorporated to allow the focal point of the appliedenergy to be manipulated to create a seal across the entire width of ablood vessel. For example, a beam may have a cross-sectional diameter ofabout 1 mm. Because the cross-sectional size of the light beam issmaller than most of the veins being treated in accordance with thisinvention, this beam would be moved across the width of the varicosevein as the vessel is held in a compressed or collapsed configuration.Or, stated differently, a beam can have a region of minimum dimension,which may be an area of maximum intensity, the minimum dimension beingabout 1 mm. In addition, the beam need not be uniaxially symmetric. Incertain embodiments, the beam may have a generally circular crosssection, but in other embodiments, the beam has a rectangular orelliptical cross-section. Providing beams with non-circular crosssections provide an advantage of being able to create a cauterized lineacross the vessel, which may require less energy than a circular cauteryzone does.

The present invention may further include an adjustment mechanism foradapting the apparatus to effectively treat the target blood vesselbased on the size and/or depth of the vessel beneath the body surface.This could be accomplished by adjusting the enabling compression rangeto suit particular conditions. The size and depth of the vein may eachact to change the pressure needed to collapse the vein. Thus, forexample, a separate probe may be provided for treating each type ofsituation. Alternatively, the enabling range could be adjusted bychanging the positions of the enabling electrical contacts within theprobe, for example by a user manipulatable threaded collar having atleast one of the electrical contacts mounted thereto.

It will be appreciated that alternative means for enabling adjustment ofthe apparatus to treat veins of varying sizes and conditions arecontemplated. For example, the apparatus may include means for adjustingthe waveband of light, to select a waveband that penetrates the bodysurface more deeply. Alternatively or additionally, a focal depth of theaiming lens can be adjusted. As yet another example, the amount ofpressure for enabling transmission of light can be adjusted such thatwhen a relatively low pressure is applied, only superficial or surfacevessels will be collapsed and occluded in preparation for the cautery.In this respect, higher pressures will permit the collapse andsubsequent treatment of deeper vessels.

Another advantageous feature of the invention is a cooling mechanismadapted to cool the body surface during the transmission of the energy,in order to prevent thermal damage to the skin and peripheral tissue.The cooling mechanism may comprise a cavity or chamber defined in adistal end region of the probe, wherein the cavity is adapted to containa substantially transparent cooling medium, such as chilled water orother aqueous solution, for example. Thus, during operation of theapparatus, heat is conducted out of the superficial tissue and into thecooling medium. Preferably, the mechanism is adapted for circulating thewater or other cooling medium to provide more effective, continuouscooling. A remote heat exchanger in fluid communication with the probemay be provided for removing heat from the circulating liquid.

In a preferred embodiment including the cooling mechanism, a liquid-freepath is defined in the probe, which may comprise a liquid-free gapdefined in the cooling medium cavity at the probe distal end region.Advantageously, this structure simplifies the optical path and thereforeenables greater control over transmission of the light into the bodysurface. As an alternative means for simplifying the optical path, thecooling medium may be a gas rather than a liquid. As a furtheradvantage, the cooling may be provided by expansion cooling by allowingthe ambient temperature gas to cool as it expands.

Any and all features described herein and combinations of such featuresare included within the scope of the present invention provided that thefeatures of any such combination are not mutually inconsistent.

These and other aspects and advantages of the present invention will bemore clearly understood and appreciated by reference to the followingdetailed description and claims, particularly when considered inconjunction with the accompanying drawings in which like parts bear likereference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of the present invention,including a varicose vein treatment handpiece, being used to treat atarget blood vessel in a leg of a patient, the handpiece including asource of light for radiating the vessel as well as a means foractivating the light source in response to a predetermined level ofcompression applied against the vessel.

FIG. 2 is a cut-away, partial cross-sectional view of the handpieceshown in FIG. 1, in which insufficient compression is being applied tothe vessel such that the delivery of light is disabled.

FIG. 3 is a view of the same handpiece shown in FIG. 2, in whichsufficient pressure is being applied to the vessel to enable delivery oflight and effective treatment of the vessel.

FIG. 4 is a view of the same handpiece shown in FIGS. 2 and 3, in whichexcessive compression is being applied to the vessel such that deliveryof the light is disabled.

FIG. 5 is a flow diagram of a method of the present invention fortreating a varicose vein.

FIG. 6 is a more detailed flow diagram of the method of the presentinvention shown in FIG. 5.

DETAILED DESCRIPTION

Referring now to FIG. 1, a blood vessel treatment apparatus, inaccordance with the present invention, is shown generally at 10,comprising a power source 12 for transmitting energy transcutaneouslythrough a body surface 16 and in proximity to a target blood vessel 18,and preferably into target blood vessel 18, for example a varicose veinin a human leg 21. The apparatus 10 preferably includes a handheldprobe, or handpiece 20, including a distal end region, hereinafterreferred to as a probe head 22, for contacting the body surface 16, anda controller 24 operatively connected thereto.

As will be described in greater detail hereinafter, the source 12 ofenergy preferably includes an energy source configured to emit asufficient amount of energy to couple two opposing sidewalls of a bloodvessel together to occlude the flow of blood therethrough. In theillustrated embodiment, power source 12 includes a visible light source26. It is to be appreciated, however, that with appropriate modificationto the apparatus 10, different forms of energy may be utilized with theapparatus disclosed herein. Power source 12 may include, for example, asource of electromagnetic radiation, a source of microwave radiation, asource of radio frequency energy, and/or a source of ultrasound energy.In one embodiment, power source 12 includes a source of electromagneticradiation, such as a light source configured to emit broadband lighthaving a wavelength or wavelengths in a range from about 300 nm to about2000 nm. In another embodiment, power source 12 includes at least onelaser diode or light emitting diode (LED). In an additional embodiment,power source 12 includes a source of microwave energy configured to emitenergy in a frequency range between about 0.9 GHz to about 3 GHz. In yetanother embodiment, power source 12 includes a source of radio frequencyenergy emitted in a frequency range of between about 100 kHz and 3 MHz.A suitable source 12 of energy is capable of safely heating the bloodvessel sufficiently to cause cauterization thereof.

The effectiveness of the wavelengths of energy chosen is dependent onseveral factors. Among these factors is the transmission of the energywavelength through the intervening tissue of the patient, and theabsorption of the energy by the target tissue. The most effectivewavelength will be absorbed by the target blood vessel but will not bestrongly absorbed by the intervening tissue. For example, when powersource 12 is a light source, far infrared wavelengths may not besuccessful despite the strong absorption thereof by the vein and theblood, since far infrared wavelengths would also be strongly absorbed bythe intervening tissue, such as the skin.

Visible light is reasonably well transmitted by the skin and reasonablywell absorbed by the vein and blood. It has been shown that longerwavelengths of visible light can be more effective for deeper bloodvessels. Since there is obviously a greater amount of intervening tissuewhen treating deeper veins, it is more important to utilize a wavebandwhich would not be substantially attenuated by the intervening tissue.

Notably, when power source 12 is a light source, wavebands near thevisible wavebands may also be advantageous. In particular, near infraredwavelengths are efficiently transmitted through the skin andsubcutaneous tissue.

In the illustrated embodiment, a broadband light source 26 may beprovided by a suitable lamp 42, for example a halogen lamp or an arclamp as is known in the art, which is constructed to provide continuoushigh intensity visible light An elliptical reflector 46 is shownadjacent the lamp 42. The light is passed through a focusing lens 48 andinto means, for example an optical fiber (not shown), for transmittingthe light to handpiece 20. More particularly, a suitable, conventionalfiber optic cable 52 may be connected between the controller andhandpiece 20 by suitable connectors 56 to the handpiece.

It is noted that instead of transmitting light though the fiber opticcable 52 into the handpiece 20 from a relatively remote lamp 42 (asshown and described herein), it is contemplated that the power source 12may be substantially or entirely incorporated into the handpiece 20 inaccordance with the invention. More generally, the power source 12 maybe arranged in any suitable, conventional manner as known in the art.

In order to eliminate undesirable wavelengths or frequencies, forexample far infrared wavelengths, the broadband light beam from the lamp42 may be passed through one or more suitable filters (not shown) beforebeing transmitted into the focusing lens 48. Alternatively, suitablereflectors may be provided. Shown in FIG. 1 is an infrared reflector 58mounted between the lamp 42 and the lens 48.

There are other well known means in common usage for removing infraredwavelengths form broadband light sources. Notably mid and far infraredlight are typically attenuated in fiber optic light cables. The lightemerging from a fiber optic bundle, stripped of the infrared, is oftenreferred to as a “cool light source.” Typically, fiber optic bundlesattenuate much of the far infrared light. Optical fiber materialgenerally transmits visible and near infrared light best. In addition,water is commonly used as an infrared filter, since water transmitsvisible light more effectively than infrared light.

Dichroic beamsplitters are also frequently utilized to separate longfrom short wavebands. One waveband of a beam of broadband light isrefracted through the beamsplitter while the other waveband is reflectedby it. The desired wavelength is then directed toward an appropriatearea By using two dichroic beamsplitters, a particular waveband can beselected from the broadband light source. The beamsplitters may bedielectric coated glass intended to be used at a 45 degree angle to abeam.

Other means may be used to select wavebands. Cutoff wavelengths may alsobe adjusted by means well known in the art For example, the generatorsof the power may be configured or adjusted to generate the desiredfrequency of energy.

Other suitable sources of electromagnetic radiation include lasers,laser diodes and LED's. Particularly in the case of the latter, an arrayof such miniature light sources may be employed to achieve the necessarypower density in the varicose vein. The multiple light sources may bedirected such that a point of convergence of light beams occurs beneaththe skin within the varicose vein. To reduce the size of the probe, thelight sources may be situated remotely, while optical fibers are used toconvey the radiation to the target site.

It is noted herein that a “pulsed” light source, as is generallyunderstood in the art, implies that power supplied to a lamp or bulb ispulsed. In other words, in a “pulsed” light source, the lamp or bulbwill only emit light when an electrical pulse is applied thereto. Incontrast, in a preferred embodiment of the present invention, acontinuous light source is used. The light source is continuouslyilluminated during the treatment.

Although preferably the light source is continuously illuminated fromthe lamp 42, the present apparatus may further comprise a shuttermechanism 60 for gating the light, with an on-time of about 0.1 secondsto continuous, as it is being transmitted into the target vessel 18. Inone embodiment, on-times of about three minutes have been demonstratedto be successful in occluding blood vessels.

Light interacts with the tissue as it enters the body surface 16. Thelight will be partially absorbed, partially transmitted and partiallyreflected. Ideally, the highest power density will occur in the bloodvessel 18 and not in adjacent tissue. Preferably, means are provided forfocusing the light from the handpiece and into the target blood vessel18. The light may be focused directly from the source 12 toward thetarget tissue, or alternatively, may be relayed by a fiberoptic waveguide (not shown). The light may be focused by refractive or reflectiveoptics, as is well known in the art. Reflective optics offer advantagesof low losses and low wavelength dispersion.

An important aspect of the invention is the formation of a stable lesionin the vessel 18, resulting from the focused electromagnetic radiation,transmitted into the target vessel 18 while the vessel 18 is held in acollapsed state. This may be more clearly understood with reference toFIGS. 2, 3 and 4, which show the varicose vein treatment handpiece 20 ingreater detail.

Specifically, a switch mechanism 62 or other suitable means are providedfor activating the radiation source 12 in response to a predeterminedlevel of compression applied against the target blood vessel 18. Asindicated above, the switch mechanism may be controlled manually orautomatically. Also as mentioned hereinabove but not shown in detail inFIG. 1, the radiation source may include an optical fiber 64. Shown incut away view in FIGS. 2-4, is a distal end region 66 of the opticalfiber 64 for radiating light through a focusing lens 68 into the targetblood vessel 18.

As a specific example, though not intended to limit the scope of thepresent invention, the switch mechanism 62 may include first and secondelectrical contacts 74, 76 respectively, disposed within the handpiece20, the contacts 74, 76 being biased apart, and not in contact with oneanother, by means of a spring 78 or the like.

Thus, only when the spring 78 is compressed within a desired range, dothe contacts 74 and 76 overlap and therefore complete an electriccircuit, enabling the transmission of radiation into the blood vessel18. The handpiece 20 may include inner member 82 housing the opticalfiber 64. A shell or outer housing 84, sized to be held in one hand byan adult human being (not shown) is slidably mounted with respect to theinner member 82. The probe head 22 is mounted to the inner member 82 andprovides means for contacting the body surface 16.

In practicing a method of the present invention, an operator (not shown)applies manual compression of the handpiece 20 against the body surface16. This causes the outer housing 84 to slide downward, against thespring 78, bringing the second contact 76 closer to the first contact74. Only when the contacts 74, 76 meet will light be delivered to thehandpiece 20, signifying that adequate but not excessive compression isbeing applied to the vessel 18.

In another embodiment not shown, the compression is applied by one ormore compression devices attached to or otherwise located on thepatient. The compression devices may include, among other things apneumatic cuff or an elastic band.. These compression devices apply thecorrect compression to hold the vessel in the desirable collapsedcondition.

FIG. 2 shows the handpiece 20 contacting the body surface 16, but littleor no compression is being applied thereto. As shown, the electricalcontacts 74 and 76 are apart, disabling the delivery of light into thevessel 18.

FIG. 3 shows the handpiece being pressed against the body surface 16with sufficient force to collapse the vessel 18. Delivery of light isenabled by the contacts 64 and 66 completing the circuit. In FIG. 3, thecollapsed vessel 18 is being radiated with and heated by the light,causing cauterization of the vessel 18.

FIG. 4 shows the handpiece as being pressed against the body surface 16with excessive force. As shown, the excessive force has not only causedcollapse of the target blood vessel, i.e. the varicose vein 18, but hasalso caused collapse of a deeper, non-target vessel 82 and other nontarget vessels which could otherwise cool the skin and protect it frombeing burnt. The second electrical contact 76 has traveled past thefirst electrical contact 74, and thus, delivery of light has beendisabled, preventing injury to non-target tissue.

As an example, the first contact 74 may be a cylindrical band ofelectrically conductive material fixed within to an internal wall of thehousing 78. The second contact 76 may be an electrically conductive leafspring.

Importantly, the predetermined level of compression is sufficient tosubstantially slow, or substantially prevent, a flow of bloodtherethrough. More specifically, the compression against the targetblood vessel 18 is sufficient to cause inner walls 88 of the vessel 18to contact one another as shown in FIG. 3.

Alternative means of compressing the vessel within a desired range arecontemplated and are considered to be within the scope of the presentinvention. Means may also be provided for monitoring the level ofcompression applied against the vessel 18. For example a small load cellcould be incorporated within the probe head 86. Logic within theinstrument 20 would enable functioning of a physician operated switch(not shown) when the load cell indicates that the applied pressure iswithin the desired range.

Preferably, the enabled pressure range is adjustable for variousconditions. For example, size and depth of the target blood vessel 18may effect the compression needed to adequately collapse the vessel 18.Means may be provided for enabling selection of the enable pressurerange. For example, a separate handpiece may be made available for eachrange. Alternatively, the enable pressure range may be adjustable bychanging location of the first or second contact 74, 76 within theprobe. More specifically, the first contact 74 may be mounted on a usermanipulatable threaded collar 94 (shown in phantom line in FIG. 3)within the handpiece 20.

Other means of adjusting the instrument for veins of various depths andsizes are contemplated. For example, since longer wavelengths of lightwill tend to penetrate the body surface more deeply, the waveband may beadjusted to target blood vessels at different depths. Alternatively, oradditionally, the focal depth of the aiming lens, and/or the beamdimensions can be adjusted using conventional means. The amount ofpressure to enable transmission of power can be adjusted such that whena lower pressure is used only superficial vessels will be ligated, whilehigher pressures still permit ligation of deeper vessels as well.

It is noted again that preferably, the flow of blood through the vesselis substantially stopped during the application of the light, otherwisethe flowing blood will tend to carry away much of the heat. In otherwords, the flowing blood may continue to cool the vein at the same timethe light source is applying heat to close the vein.

However, the presence of a small amount of blood between the collapsedwalls is acceptable and desirable, as long as the flow has substantiallyceased. The volume or aliquot of blood present in the collapsed veinwill absorb a fraction of the light, thereby forming a stable clot whichwill maintain interruption of subsequent blood flow and prevent orreduce a chance of recanalization of the vessel 18. When the vesselwalls 88 are held in contact as hereinabove described, the stability ofthe resulting lesion is much greater than mere clot formation by heatingalone. In other words, a more stable closure is achieved by cauterizingthe vessel while opposing surfaces are held in apposition.

It is important that a good cosmetic result is achieved. A large bloodclot “cord” or a bumpy skin surface resulting from the procedure wouldbe unsatisfactory. Thus, again, it is important to exclude most bloodfrom the vessel while the cautery is taking place.

Advantageously, referring now to both FIGS. 1 and 3, the presentinvention may further comprise a cooling mechanism 100 adapted to coolthe body surface 16 during transmission of the electromagneticradiation.

Light is passed through skin and subcutaneous tissue 102 before itreaches the vein 18 to be cauterized. Ideally, this intervening tissue102 would absorb insubstantial amounts of light and thus the temperatureof the tissue 102 would not rise appreciably. However, the interveningtissue 102 may absorb significant portions of the light which in theabsence of cooling could possibly causing blistering or other thermaldamage. The cooling mechanism 100 is provided to cool these structures102. One means of achieving effective cooling is to conduct heat awayfrom the body surface 16 through the probe head 22.

For example, the cooling mechanism 100 may include a circulationassembly for circulating a cooling fluid comprising a suitable mediumsuch as clear water, between a fluid source 104 and the probe head 86.As shown in FIG. 1, the fluid source 104 may include a remote heatexchanger 106 adapted to remove heat from the cooling fluid passed fromthe handpiece 20. A peristaltic pump 108, or the like, may provide meansfor circulating the fluid, for example in a flow direction representedby arrows 111 through a fluid conduit 112 connected between the heatexchanger 106 and the handpiece 20.

Turning now specifically to FIG. 3, a cooling medium cavity, or chamber114 is defined in the handpiece 20 adapted and positioned to effectivelyremove heat from the body surface 16 during the treatment in order toprevent thermal injury to the patient. As shown, the cooling chamber 114includes coolant supply tube 116 and coolant exhaust tube 118, in fluidcommunication with the coolant conduit 112, and defining inlet 126 andoutlet 128, respectively, for allowing the cooling fluid to pass throughthe cooling chamber 114.

The probe head 86 may include a thin, clear glass window 120 centered bymeans of a heat conducting flange 122, such as a metal flange. Thisstructure promotes rapid and continuous conduction of heat from thetissue and into the probe head 22. The window may be constructed ofother thin clear materials such as acetate, polyethylene or sapphire.

Preferably the thickness of the cooling chamber 114 is kept thin toreduce optical attenuation.

In a preferred embodiment including the cooling mechanism, a liquid-freepath is defined in the handpiece, which may comprise a liquid-free gap128 shown in phantom line in FIG. 3, defined in the cooling mediumcavity in the probe head 86. In other words, the cooling medium cavity114 may be substantially donut shaped. Advantageously, this structuresimplifies the optical path and therefore enables greater control overtransmission of the light into the body surface 16.

As an alternative means for simplifying the optical path, the coolingmedium may be a gas rather than a liquid. It is contemplated that thegas could cool the probe head 22 and the tissue primarily by expansioncooling. For example, as the gas is allowed to expand in the probe head86, heat will be absorbed therefrom, thereby cooling the tissue 102. Oneor more refrigerants known in the art could also be used for thisapplication. For example, low molecular weight non-toxic organic gasesare used in certain embodiments to achieve the desired cooling. In otherembodiments, cooling could be obtained by expansion cooling methods, byusing compressed air, which is not necessarily liquefied air. As yetanother alterative, the cooling could be achieved by a thermoelectricgeneration, i.e. the Seebeck effect, as will be understood by thosefamiliar with the art.

The apparatus herein above described is suitable for performing a methodin accordance with the present invention for occluding a blood vessel,such as a varicose vein, the method generally comprising the stepsdescribed in detail herein above. FIG. 5 shows a simple flow diagram ofa method of the present invention for treating a varicose vein. FIG. 6is a more detailed flow diagram of the method of the present inventionshown in FIG. 5.

In a preferred embodiment, the application of energy and compression areapplied for a duration known to safely and effectively occlude avaricose vein. The amount of energy, compression, and the duration ofeach are preferably determined by the operator of the apparatus of theinvention, and will vary depending on person being treated In anadditional embodiment there will be feedback control to reduce thepossibility of inadvertent thermal damage. The control may be comprisedof any suitable means, including safety and efficacy features. Forexample, it is preferable to monitor the temperature of the vessel whileit is being treated. Since the procedure is preferably non-invasive,monitoring of the temperature may be estimated by the empiricallymeasured relationship between surface temperature and subcutaneoustemperature for the particular heating time and rate and cooling timeand rate. A miniature thermocouple or other temperature sensor, may beincorporated to monitor temperature at the skin surface adjacent to theregion of treatment or to monitor the temperature of a cooling mechanismof the apparatus.

Feedback of skin temperature may be relayed to the controller whichwould automatically adjust either the heater power or the cooling tokeep the temperature within a desired range for a desired time.

Pressure applied to the vessel, as mentioned briefly hereinabove may bemonitored, and feedback data relayed to the controller. Pressuremonitoring may be accomplished by incorporating within the system a loadcell or pressure transducer or other monitoring means known in the art.Formation of the lesion induced by the apparatus of the presentinvention can also be monitored and measured, using for examplereflection measurements made at two wavelengths to yield a ratiometricmeasurement. As a lesion is generated in the treated vessel, thereflection signal from venous blood should decrease while the reflectionsignal from clot and lesion will increase. These measurements may bemade transcutaneously as is well known in the art. In additionalembodiments, a spectroscopic sensor may be provided to monitor theprocedure and the generation of the blood vessel occlusion.

While this invention has been described with respect to various specificexamples and embodiments, it is to be understood that the invention isnot limited thereto and that it can be variously practiced within thescope of the following claims.

1-39. (canceled)
 40. A method for occluding a target vein, the methodcomprising the steps of: maneuvering a mechanical device to reduce alumen dimension in an elongated segment of the vein; and during a timeperiod in which the segment has the reduced lumen dimension, applying asufficient non-compressive energy to the segment to permanently stopblood flow through the segment.
 41. The method of claim 40 wherein themechanical device comprises a handheld probe.
 42. The method of claim 40wherein the reduced lumen dimension comprises collapsing of the segment.43. The method of claim 40 wherein the step of reducing the lumendimension comprises reducing blood flow through the segment.
 44. Themethod of claim 40 wherein the step of reducing the lumen dimensioncomprises trapping blood in the segment.
 45. The method of claim 40wherein the step of applying the energy comprises applyingelectromagnetic energy in a visible range.
 46. The method of claim 40wherein the step of applying the energy comprises applyingelectromagnetic energy at a near infrared wavelength.
 47. The method ofclaim 40 wherein the step of applying the energy comprises pulsing theenergy.